â€œMost industrial fasteners are covered by two basic standards: one for materials and properties; the other, for dimensions and tolerances. Specifications for materials and properties are published by the American Society for Testing and Materials (ASTM), although other groups such as the Society of Automotive Engineers (SAE) also publish specifications covering these requirements. Standards for dimensions and tolerances are issued by the American National Standards Institute (ANSI) in cooperation with the American Society of Mechanical Engineers (ASME) and the Industrial Fasteners Institute (IFI).Where applicable, published specifications covering a particular fastener will be referenced in the section of this booklet dealing with that fastener. When referring to standards and specifications, we will use only the well-known initials of the above societies-ANSI, ASME, IFI, ASTM and SAEâ€
These include a vast range of sizes and types stocked by distributors and manufacturers for an almost limitless range of applications: the assembly and maintenance of vehicles, appliances, farm equipment, construction equipment, industrial and plant machinery of all kinds, furniture and toys. Wherever thereâ€™s a need for holding parts together, holding them apart, holding them up, or holding them down, a standard fastener can usually be found to do the job efficiently and economically. Modern industrial fasteners are manufactured to a variety of standards covering dimensions, tolerances, materials, mechanical properties, testing procedures, etc.
ASME ST-LLC does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in this document, and does not undertake to insure anyone utilizing a publication against liability for infringement of any applicable Letters Patent, nor assumes any such liability. Users of a publication are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility.
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â€œMost ASTM and ASME standards list the steel grades by their UNS (Unified Numbering system) numbers but also make reference, where appropriate to the more general AISI (American Iron and Steel Institute) grade designations. These grade numbering systems are widely used in the USA, where they originated and are recognised by most stainless steel specifiers and users. The American Iron and Steel Institute (AISI) developed designations such as 304, 430 etc and published compositions for these in their â€˜Steel Products Manualâ€™ (1974).
These are NOT specifications, but steel grade composition ranges only.
These grades were used by the American Society Testing and Materials (ASTM) to identify grades in a wide range of standards they published for stainless products, such as sheets and plates (ASTM A240), bars (ASTM A276) and tubes (ASTM A269). The compositions of the AISI grades were made more specific with the introduction of the â€˜Unified Numbering Systemâ€™, jointly established by ASTM and SAE (Society of Automotive Engineers). This five digit number, preceded by the letter â€˜Sâ€™ for most stainless steels, identified the specific variant of the gradeâ€.